Shot shell



riwtma 10, .1938

* -omEo'-. STATES .he invention relates to a loaded cartridge and moreparticularly a cartridge in the nature .of a loaded shot shell employing a double base fpowder suchas nitrocellulose-nitroglycerin .pow- I 1 der. application is a division .of application 'Seria1 Number 667,975, filed October 6, 19.23,

:" Patent No. 1,757,584, issued May 6, 1930.

I Q ders is often accelerated by the addition of niv 1 apropellant'charge which will burn quickly and i In a'. cartridge employing such a powder, ,the

v -maximum pressure is not developed or sustained 151 for any appreciable distance along the gun bar I powder, and more particularly a nitrocellulosenitroglycerin powder, which powder is in such formfso modified and so .primed and so confined k a as to burn progressively when fired in a shot Further objects will appear from the detail description, in which will'be describedan illustrativeembodiment of this invention; it will be understood, however, that thisinvention is not limited. to the specific embodiment disclosed.

In accordance with this invention ashot shell comprising, a case or shell, a coordinative primer therein, a shokcharge and wadding, has a shotpropelling charge of a double base powder which 40 is made progressive lburning by retardation of its initial combustion rate. This may be accomplished by'rnodification of-the grain, as by sur--: face treating thegrain with a deterrent andby proper priming and confining of the powder '45 charge. An illustrative embodiment of this in vention comprises a nitrocellulose nitroglycerin powder grain surface treated with dinitro-toluene. The double base powder is surface-modified V or treated in coordination with the primer to sub- ;50stantiallyretardits initial combustion rate and 'tl'ie accelerator in the interior of the grain is f afdapted in coordination with the retarder or Q ,d'eterent to maintain a fast subsequent burning ;;,fate, as by making the nitroglycerin content such 85 to secure that result.

' The burning action of densenitrocellulose powmitroglycerin. Such a powder, however, produces I may be almost consumed. at the initial stage.

rel, but the initial pressure drops rapidly to its u pelllng charge, of granular double base smokeless PATENT OFFICE SHOT SHELL John M. Olin, Alton, 111., assignor to Western Cartridge Company, East Alton, 111., a corporation 'of Delaware NoDrawing. Original application October 6,

192 3,-S0l'i8.l N0. 667,075. Divided and this application April 30, 1930, Serial No. 448,800

5 Claims. (01. 102-15) A double base'powder of this character when loaded in a shot shell and when suitably primed and confined with reference to its surface and core; will cause the shot charge to be propelled at v,powder when employed in a shot shell for propelling the shot charge, not only materially reduce the stringing of shot but also improve the pattern.

, The propellant charge is properly coordinated- "with the other components ofthe shot shell, by coordination with the primer, the wedding. and the shotcharge; The primer, therefore, is preferably a comparatively hot primer so as to insure ignition of the surface treated grains as well as continuatiorrof the burning of the powder charge,

while the wadding-ls madesuihclently heavy to secure the desired confining of the powder charge in order to cause the pressure to be maintained, so as to insure the continuation of the burning of the powder.

In accordance with this invention, a double base powder,.'such as nitrocellulose-nitroglycerin powder designed for use in a shot shell, is treated so as to, burn progressively. 'This can be accomplished by surface treating'such a powder, containing the desired percentage of nitroglycerin and granulated or sub-divided tothe desired or required granulation, such as thirty mesh in any suitable manner so as to render it progressive burning. A deterent whichls particularly suitable is dinitro-toluene, which can .be applied-inany manner, as by rumbling in a rotating drum at a temperature of about 80 C. for aboutonehalf hour, using about 2% of the deterrent relative to the weight of the powder,so that the powder grains will become impregnated with the deterrent. It will be understood that the above is simply an illustrative embodiment; for the amount of thedeterrent employed and the period of treatment, and to some extent even its temperature, as well as other conditions oftreatment, will vary with and depend upon the charis to subdivide the powder to an extent sumcient,

to the type of cartridge specifically described, it

acterand composition of the powder grain, of the deterrent employed and the intended use of the powder, as well as the desired characteristics which this powder grain is to have. The object and to impregnate each powder grain of the desired composition to an extent sumcient and with sufiicient of the deterrent to cause the powder when confined and primed, as previously described, to burn progressively when fired in a shot gun.

As a further illustrative embodiment of this invention, a progressive burning double base powder can be secured by incorporating with the nitrocellulose and nitroglycerin where the percentage of nitroglycerin is high (35%-40%), and

preferably during the course of manufacture, a cooling or slowing-agent having the action of reducing the temperature of burning and slowing up the combustion in such a manner as to produce the desired result followed by a surface treatment as described. There are many compounds which may be used 'for' this purpose, among them being: Vaseline and similar products, alkaline bi-carbonates, either alone or mixed with vaseline, diethyl diphenylurea, dimethyl diphenylurea, cyanamide, tartrates, olive oil, castor oil, fats and resins, soaps, oxalates, starch, dextr ine, and diphenylamine. All of these are classed as deterrents and they may be incorporated with the nitrocellulose base together with the nitroglycerin. Such nitrocellulose-nitroglycerin powders, containing from 35% to 40% of nitroglycerin, together with a cooling or slowing agent of the character described, may be surface treated with dinitrotolueneas heretofore described. It will be understood that the above is simply illustrative of an embodiment of this invention; for the percentage of nitroglycerin and the character of the slowing agents if employed will vary, of

,course, with the characteristics which the powder is to have, as well as the uses to which it may be put and the situations in which it may be employed. It will be understood in this connection that nitroglycerin serves as a component of the core to sustain the combustion, and also to overcome to some extent the delayed ignition characteristics imparted by the surface treatment.

In accordance with this invention a shot shell is produced in which the powder will burn progressively so as to develop its energy in such a manner'that the energy released and imparted to the shot charge is very much greater for the same and limiting breech pressures than in shells using other powders. In the shell embodying this invention, a given charge of shot (such as 1% oz. in a 12 gauge shell) 'can therefore be propelled a greater distance as compared to other shells;

accordingly, a greater shot charge can be pro- 7 jected thesame distanceas in other shells using other powder; and all at the same limiting and safe' breech pressures. This means that the shell embodying this invention will operate in a zone of high energy transfer at safe breech pressures because the powder will burn progressively in such a zone. The range and @ttern is improved and shot stringing decreased. 7

While the invention is particularly applicable subsequent burning rate.

will be understood'that the invention is applicable as to many of its aspects to other forms and types of cartridges. It will further be understood that while dinitrotoluene has-been specifically referred to as a deterrent, other suitable deterrents.

having the desired properties and imparting tothe powder of thedesired composition the desired characteristics, may be employed. It will furthermore be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations; that is contemplated by and V is within the scope of the appended claims. It is furthermore obvious that various changes may be made in details, within the scope of the appended claims, without departing from the spirit of this invention. It is therefore to be understood that I this invention is not to be limited to the specific details described. Y

Having thus described the invention, what is claimed is:

1. A loaded shot shell comprising a case or which is surface-treated with dinitrotoluene in coordination withthe primer to substantially re tard the initial combustion rate. U

3. A loaded shot shell comprising a case or shell, a coordinative primer therein. a shot charge, wadding, and a shot-propelling charge of powder grains containing at their surfaces 8. retarder of combustion coordinated with the primer to substantially retard the initial combustion rate, said grains having in their interiors an accelerator of combustion adapted in. coordination with the retarder to maintain -a fast subsequent burningrate.

4. A loaded shot shell comprising a case or shell, a coordinative primer therein, a shot charge, wadding, and ashot-propelling charge of granular double base smokeless powder, viz. nitrocellulose-nitroglycerin powder, which is surface modified in coordination with the primer to. substantiallyretard the initial combustion rate, the nitroglycerin content being such in coordination with the surface modification as to maintain a fast subsequent burning rate.

5. A loaded shot shell comprising a case or shell, a coordinative primer therein, a shot charge, wadding, and a shot-propelling charge ofsmokeless powder grains composed of nitrocellulose'containing nitroglycerin and a deterrent, said grains'being surface-treated witha deterrent-coordinated with the primer to substantially retard the initial combustion rate, and

the nitroglycerin content being such in coordi-' nation with the deterrent as to maintain a fast JOHN M. OLIN. 

